Current collector



Oct. 8, 1-963 G. MOHRING CURRENT COLLECTOR Original Filed Oct. 25. 1957 4 Sheets-Sheet 1 INV EN TOR.

jam-Av Oct. 8, 1963 G- MOHRING CURRENT COLLECTOR 4 Sheets-Sheet 2 Original Filed Oct. 23. 1957 INVENTOR.

BYQQHQYA.

Oct. 8 1963 G. MQHRING 3,106,272

CURRENT COLLECTOR I Original Filed Oct. 23. 195'? 4 Sheets-Sheet 3 Oct. 8, 1963 'G. MOHRING 3,105,272

CURRENT COLLECTOR Original Filed Oct. 25. 1957 l 4 Sheets-Sheet 4 Fly. 7

IN VEN TOR. m-Ymm-Q. mo' rrlng- United States Patent 3,106,272 CURRENT COLLECTOR Gerhard Mohring, Schuttorf, Germany, assignor to This application is a continuation of my copending application Serial No. 691,990, filed October 23, 1957, now abandoned.

My invention relates to current collectors of the pantograph type, especially for high-speed electrically driven vehicles.

It is an object of my invention to provide an improved current collector of said type having a frame supporting two parallel collector shoes frictional ly engaging an overhead line.

Known current collectors of said type are so constructed that the rear and the front collector shoe bear with equal pressure against the overhead line; this is disadvantageous for high travelling speeds and makes the collector heads unreliable.

It is accordingly a more specific object of my invention to provide current collectors of this type in which increased resistance on the leading contact shoe, normally causing tilting of the collector in a direction to move the trailing contact shoe away from the trolley wire, will result in increased pressure being exerted on the trailing shoe in a direction to cause it to bear more firmly against the trolley wire.

Accordingly, the frame supporting the two shoes is resiliently attached to the pantograph structure to permit a relative up and down movement thereof in addition to a tilting movement so that sudden shocks or impulses upon the pantograph. structure, which occur at high speeds, are absorbed before being transferred to said frame and the shoes supported thereby, and that pressures upon the leading shoes are balanced and trailing.

. These and other objects and advantages of my invention will become apparent to those skilled in the art from the following detailed description of certain embodiments of the invention when read in conjunction with the appended drawings in which FIG. 1 is a front elevation view of the current collector head according to my invention;

FIG. 2 is a cross-sectional view taken through the centre of the collector head of FIG. 1;

FIG. 3 is a front elevation view of another embodiment of my invention;

FIG. 4 is a partial top plan view thereof;

FIG. 5 is a side elevation view thereof;

FIG. 6 is a side elevation view of a slightly modified embodiment;

FIG. 7 is a transverse cross-sectional view to be read with FIG. 5; and

FIG. 8 is a transverse cross-sectional view of the embodiment shown in FIG. 6.

, Referring to the drawings, and more specifically to FIGS. 1 and 2 thereof, the current collector head is swingably mounted upon the uppermost joint pins a of the collapsible pantograph frame p and parts of the current collector head are displaceable vertically and horizontally relative to pin a, as will be described. Said current collector head comprises a tubular shaft b connecting opposing joint pins a, guide or suspension members 0 integrally attached to said shaft b, supports e for the contact shoes g, and pins f, constituting supporting means, extending from said supports e and engaging a vertical longitudinal slot f in each of the guide members 0. The bolts or pins a are secured against axial displace- 3,106,272 Patented 0a. s, 1963 ice ment in the pantograph frame and extend therebeyond inwardly toward each other. The projecting ends of these pins or bolts are telescoped into the tubular shaft b. Each of a pair of symmetrically arranged tension springs k k has one end attached to a pin 2 of each guide member 0 and its other end attached to the uppermost links p of the pantograph frame. These springs guide and properly orient the collector head when the pantograph is retracted to withdraw the collector head from engagement with an overhead trolley. The springs k k are effective only during extension and retraction of the pantograph, and have substantially no effect upon the operation of the collector head when the latter is in engagement with the trolley wire and when the vehicle is moving.

The contact shoes g with their customary extensions h and their supports e form a rigid unit which may not only swing about the pinions f but also be displaced in vertical direction within limits of said slots f. Said unit is held in the neutral position shown in FIG. 2 by a pair of biased compression springs d d The compression springs d d as will be observed from FIGS. 1 and 2, are considerably heavier and stronger than the relatively light tension springs k k The springs k are merely to maintain the collector unit in a normal position, or properly oriented, during raising and lowering of the pantograph, and play no part in the operation of the current collector after the pantograph has been erected sufficiently to engage the contact shoes g with the trolley wire. The relatively heavy compression springs, d and d are the only springs acting effectively upon the collector unit during actual operation when the shoes g are engaged with a trolley wire. The relatively heavy compression springs d d are mounted upon telescoping spindles attached to said unit and to the guide members 0, respectively. It will be noted that the pins 1 are radially offset from the axis of the connecting tubular rods b. Therefore, when the collector is moved in the direction of the arrow V, shocks or resistance encountered by the leading contact shoe g are transmitted, through its support e, to the pins f and tend to rotate the guide members 0 in a counterclockwise direction, as viewed in FIG. 2. This will tend to further increase the pressure of the spring d and to decrease the pressure of the spring d Consequently, such shocks and resistance will therefore cause a greater pressure of the trailing contact shoe g against the trolley wire.

The pressure shift as a result of increased frictional resistance of the overhead line, and of wind resistance, especially at high speeds, may be explained as follows. The wind pressure on the pantograph frame will cause the latter, due to its parallel linkage construction, to become compressed laterally, or longitudinally of the direction of travel, and thus to extend in a vertical direction. With the two shoes g bearing against the trolley wire, this will result in a downward movement of the pins 1 in the slots f relative to the member 0, thus increasing the radial distance between pins 1 and the axis of the hollow rod b or, in other words, increasing the distance at which torque tending to rotate the guides 0 will act relative to the axis of the tubular rod b. Consequently, any increase in frictional resistance on the leading contact shoe g will be even more effective in tending to rotate the guides c to compress the spring d and thus to increase the pressure of the trailing contact shoe g on the trolley wire, there being a corresponding decrease in the pressure of the spring d The shifting of the pressure between the springs d d imparts to the current collector head a resiliency permitting its adaptation to any uneveness of the overhead line so that shock effects and wear and tear of the current collector are avoided or at least reduced.

The current collector shown in FIGS. 3 to 6 comprises two parallel collector shoes generally indicated at 1, which are rigidly connected at or near their ends by yoke-like supports 2 to form a stiff frame hereinafter referred to by the reference 1-2. Each of these supports 2 is provided with a resilient joint member 3 (FIGS. 5 and 7) or 3' (FIGS. 6 and 8) respectively, which allows the said frame 1-2 to perform not only an up and down movement relative to the pantograph frame 8 but also a rocking movement relative thereto. Each of said joint members 3 and 3' comprises a casing 5 or 5', respectively, which houses a spring 4. The two casings 5 or 5' within one collector frame 1-2 are connected by a carrier member 6 located intermediately of the collector shoes 1. This carrier member 6 is provided with downward projecting lugs 7 which receive the joint pivots 9 of the uppermost links of the pantograph frames 8. The pivots 9 of opposing frames 8 are connected by a link member 10 to which member 6 is secured intermediate its ends as best seen in FIG. 3.

The joint member 3 shown in FIG. 7 comprises a casing 5, a compression spring 4 within said casing and resting on the bottom wall thereof and, a spring plate 16 with a tie rod 15. This rod is attached to an upper metal plate 14 which, together with a lower metal plate 12 encloses and firmly holds a resilient cushion 11 consisting for example of rubber. Said lower metal plate 12 is rigidly connected to the support 2 by a screw 13 or the like. It will be well understood that the beforesaid joint member will permit the collector frame 12 not only to move up and down but also to tilt as indicated by the dotted showing.

FIG. 8 illustrates a modified joint member 3 the solid cushion 11 shown in FIG. 7 being replaced by a resilient hollow cylindrical body 17 provided with rigidly attached (for example by vulcanization) cover plates 18 and 19. The lower plate 18 is fixed by means of a screw 22 to the support 2, the end of the screw lying within the cavity of the body 17 and constituting a ball socket 23. A tie rod member 24 acting on the spring plate 16 resting on the upper end of the spring 4 is rotatably mounted in the ball socket 23 by means of a ball 25 in such a manner that the pull member 24 with the ball 25 is safely held by the ball socket 23 which encompasses the ball 25 beyond its largest diameter.

The action of the current collector shown in FIGS. 3 to 8 is substantially the same as the one previously described and shown in FIGS. 1 and 2. Owing to the increase of the frictional resistance during increasing travelling speed, the resulting increased pressure is automatically shifted from the frontal contact shoe to the rear contact shoe by tilting the frame 12, such tilting being made possible by the resilient body '11 or -17 of the joint member 3 or 3', respectively.

More specifically, the current collectors shown in FIGS. 3 to 8 operate substantially as follows. The axis of oscillation of the guides 3 or 3 is the axis of the pins 9 and, due to the connection of the frames 2 to the lower ends of the suspension members 3, and through a resilient coupling such as 11 or 27, there is a second axis of oscillation of the frames 2 about a point substantially adjacent the lower ends of the suspension means 3. Thus, in this latter case, and referring particularly to FIG. 7, if there is increased frictional resistance upon the leading contact shoes 27', this will be transmitted through the frames 2 as a horizontal force directed against the forward ends of the suspension means 3. This will cause the suspension means 3 to swing counterclockwise, as viewed in FIG. 7, and through the connecting member 6 and the ear 7, about the axis 9 of the uppermost pivot joint of the pantograph structure. As a result, the pressure exerted by the rear contact shoes 27" is increased and that exerted by the front contact shoes 27' is decreased, this resulting in a substantial equalization of the pressure on the front and rear contact shoes.

Again referring particularly to FIG. 7, it will be'clear that the counterclockwise turning of the frames 2 will increase the compression forces in the right or rear sides of the cushion members 111 and decrease the compression forces in the left or front sides thereof. This will further increase the pressure of the rear shoes, against the wire, relative to the pressure of the front contact shoes thereagainst.

In the arrangement shown more particularly in FIGS. 6 and 8, the operation is the same as that shown in FIG. 7. Here again the resultant turning of the frames 2 in a counterclockwise direction, as view in FIG. 8, and due to the transmission of horizontal forces to a point on the suspension means 3' spaced substantially downwardly from the pivotal mounting about the axis of pins 9, results in compression of the trailing portions of the tubular cushion members 17 and a decrease in the compression of the forward portions thereof.

It will thus be apparent that the arrangements of FIGS. 3 through 8 operate in the same manner as do that of FIGS. 1 and 2 by virtue of the fact that the point of application of the horizontal forces due to frictional resistance of the front contact shoes is applied at a distance, or torquearm, substantially below the uppermost axis of the pantograph structure, resulting in a torque which increases the pressure on the rear contact shoes and decreases the pressure on the front contact shoes until these pressures are substantially balanced.

In the embodiment of FIG. 6 two single contact shoes 26 are provided on the frame 12 while in the embodiment of FIG. 5 two twin contact shoes 27 and 27 are provided.

While specific embodiments of my invention have been shown and described in detail to illustrate the application of the principles of my invention, it will be well understood that my invention may be otherwise embodied without departing from such principles and without avoiding the scope of the appended claims.

What I claim as my invention is:

1. A current collector including a collapsibly jointed pantograph structure, a frontal contact shoe, and a rear contact shoe extending in spaced substantially parallel relation transversely of the direction of travel; said cur rent collector comprising, in combination, a rocking frame rigidly interconnecting and supporting said shoes; suspension means pivotally mounted on said pantograph structure for swinging about a first transverse axis including the uppermost joint of said pantograph structure; and supporting means, including resilient means, supporting said rocking frame, substantially midway longitudinally of its ends, on said suspension means at a point on said suspension means below said uppermost joint, for oscillation of said frame about a second transverse axis spaced below said first transverse axis; said resilient means normally resiliently constraining said rocking frame to a position wherein said second axis is vertically below said first axis and said shoes lie substantially in a common horizontal plane; whereby frictional forces exerted substantially horizontally of said frontal shoe will exert, through said rocking frame, a torque on said suspension means at substantially the location of said second axis, to rock said suspension means rearwardly about said first axis to increase the pressure of said rear shoe against the trolley wire; said resilient means further providing for resiliently constrained relative vertical displacement of said rocking frame and said uppermost joint.

2. A current collector including a collapsibly jointed pantograph structure, and a front contact shoe and a rear contact shoe extending in spaced substantially parallel relation transversely of the direction of travel; said current collector comprising, in combination, a rocking frame rigidly interconnecting and supporting said shoes; first horizontally extending shaft means located midway between and lower than said shoes and forming an extension of the pivot of the uppermost joint in the pantograph struoture; at least one guide member suspended from said first shaft means for swinging about the axis thereof, said guide member being formed with a vertically extending relatively elongated guide slot; second horizontally extending shaft means secured to said rocking frame substantially midway longitudinally of the ends thereof and slidably and oscillatably engaged in said slot; and resilient balancing means interconnecting said rocking frame and said guide member, said resilient balancing means normally constraining said rocking frame to a position wherein said second shaft means is vertically below said first shaft means and said shoes lie substantially in a common horizontal plane, said resilient balancing means further providing for resiliently constrained relatively vertical displacement of said second shaft means longitudinally of said slot; whereby frictional forces exerted substantially horizontal of said frontal shoe will exert, through said rocking frame, a torque on said guide member at substantially the location of said second shaft means, to rock said guide member rearwardly about the axis of said first shaft means to increase the pressure of said rear shoe against the trolley wire.

3. A current collector, as claimed in claim 2, in which said resilient balancing means comprises a pair of telescoping links each connected, at one end, to a respective end of said rocking frame; the opposite ends of said telescoping links being connected to said guide member at 7 points lying in a common horizontal plane but spaced equidistantly longitudinally of the direction of travel,

1 from the center line of said slot; and coil springs embracing each telescoping link and engaged between said guide member and said rocking frame,

4. A current collector according to claim 5 wherein the articulated joint connecting the lower portion of each suspension member to the middle portion of the associ- 6 ated rocking frame is formed by an elastic cushion member.

5. A current collector including a collapsible jointed pantograph structure, and a frontal contact shoe and a rear contact shoe extending in spaced substantially parallel relation transversely of the direction of travel; said current collector comprising, in combination, a rocking frame rigidly interconnecting and supporting said shoes; horizontally extending shaft means located midway between said shoes and above the mid-portion of said rocking, frame and forming an extension of the pivot of the uppermost joint of the pantograph structure; resiliently constrained extendable suspension means operatively associated with each frame member, each suspending means having its upper end secured to said shaft means and its lower end having an articulated connection to the mid-portion of the associated rocking frame; whereby frictional forces exerted substantially horizontally of said frontal shoe will exert, through said rocking frames, a torque on said suspension means at a level substantially below said shaft means, to rock said suspension means rearwardly about the axis of said shaft means to increase the pressure of said rear shoe against the trolley wire.

References Cited in the file of this patent UNITED STATES PATENTS 817,846 Greenwood Apr. 17, 1906 867,007 Boyes et al Sept. 24, 1907 1,253,661 Aalborg Jan. 15, 1918 1,570,933 Bennington Jan. 26, 192 6 FOREIGN PATENTS 731,234 Germany Feb. 4, 1943 

1. A CURRENT COLLECTOR INCLUDING A COLLAPSIBLY JOINTED PANTOGRAPH STRUCTURE, A FRONTAL CONTACT SHOE, AND A REAR CONTACT SHOE EXTENDING IN SPACED SUBSTANTIALLY PARALLEL RELATION TRANSVERSELY OF THE DIRECTION OF TRAVEL; SAID CURRENT COLLECTOR COMPRISING, IN COMBINATION, A ROCKING FRAME RIGIDLY INTERCONNECTING AND SUPPORTING SAID SHOES; SUSPENSION MEANS PIVOTALLY MOUNTED ON SAID PANTOGRAPH STRUCTURE FOR SWINGING ABOUT A FIRST TRANSVERSE AXIS INCLUDING THE UPPERMOST JOINT OF SAID PANTOGRAPH STRUCTURE; AND SUPPORTING MEANS, INCLUDING RESILIENT MEANS, SUPPORTING SAID ROCKING FRAME, SUBSTANTIALLY MIDWAY LONGITUDINALLY OF ITS ENDS, ON SAID SUSPENSION MEANS AT A POINT ON SAID SUSPENSION MEANS BELOW SAID UPPERMOST JOINT, FOR OSCILLATION OF SAID FRAME ABOUT A SECOND TRANSVERSE AXIS SPACED BELOW SAID FIRST TRANSVERSE AXIS; SAID RESILIENT MEANS NORMALLY RESILIENTLY CONSTRAINING SAID ROCKING FRAME TO A POSITION WHEREIN SAID SECOND AXIS IS VERTICALLY BELOW SAID FIRST AXIS AND SAID SHOES LIE SUBSTANTIALLY IN A COMMON HORIZONTAL PLANE; WHEREBY FRICTIONAL FORCES EXTEND SUBSTANTIALLY HORIZONTALLY OF SAID FRONTAL SHOE WILL EXERT, THROUGH SAID ROCKING FRAME, A TORQUE ON SAID SUSPENSION MEANS AT SUBSTANTIALLY THE LOCATION OF SAID SECOND AXIS, TO ROCK SAID SUSPENSION MEANS REARWARDLY ABOUT SAID FIRST AXIS TO INCREASE THE PRESSURE OF SAID REAR SHOE AGAINST THE TROLLEY WIRE; SAID RESILIENT MEANS FURTHER PROVIDING FOR RESILIENTLY CONSTRAINED RELATIVE VERTICAL DISPLACEMENT OF SAID ROCKING FRAME AND SAID UPPERMOST JOINT. 